Figure 3 shows scatter plots of the relationship between CA IX score and these two predictive variables. No significant correlation is seen between CA IX score and either HER2 ratio or TOP2A ratio (n=140). Thus, CA IX is a predictive marker of outcome in early-stage breast cancer patients treated with doxorubicin independent of HER2 and TOP2A amplification. This evidence concerns the gene ERBB2 and breast carcinoma.